Centre of Research Excellence in Corrosion, Research Institute , King Fahd University of Petroleum and Minerals , Dhahran 31261 , Saudi Arabia.
Corrosion Research Laboratory, Department of Mechanical Engineering, Faculty of Engineering , Duzce University , 81620 , Duzce , Turkey.
ACS Appl Mater Interfaces. 2018 Aug 22;10(33):28112-28129. doi: 10.1021/acsami.8b09487. Epub 2018 Aug 13.
The possibility of utilizing dextran as a green corrosion inhibitor for steel in strong acid environment was explore using weight loss, electrochemical (electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), potentiodynamic polarization (PDP), and linear polarization (LPR)) supported with surface analysis via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. The effect of molecular weight, temperature, and modification on the inhibition efficiency of dextran was also studied. Results from all the applied techniques reveal that dextran exhibit moderate anticorrosion property toward St37-2 steel dissolution in 15% HSO solution. Dextran with molecular weight of 100 000-200 000 g/mol (Dex 1) exhibited the highest inhibition efficiency of 51.38% at 25 °C. Based on PDP results, dextran behaved as a mixed type corrosion inhibitor. Inhibition efficiency of dextran varies inversely with molecular weight but directly with temperature. Two modification approaches, namely incorporation of silver nanoparticles (AgNPs) into dextran matrices and combination with 1 mM KI were adopted to enhance the inhibition efficiency of dextran and the approaches proved effective. The protective capability of Dex 1 has been upgraded from 51.38% to 86.82% by infusion of AgNPs and to 94.21% by combination with KI at 25 °C. Results from the study on the effect of temperature reveals that Dex 1 + KI mixture could synergistically offer 99.4% protection to St37-2 steel in 15% HSO environment at 60 °C. Surface analysis results confirm the presence of additives molecules on the studied metal surface. XPS results disclose that AgNPs are in oxide form while iodide ions are in the form of triiodide and pentaiodide ions on the metal surface. Modified dextran is a promising candidate for application as corrosion inhibitor in acid induced corrosive environment.
利用葡聚糖作为强酸环境中钢的绿色缓蚀剂的可能性进行了探索，采用失重法、电化学（电化学阻抗谱（EIS）、电化学频率调制（EFM）、动电位极化（PDP）和线性极化（LPR））结合扫描电子显微镜（SEM）、能谱（EDAX）、原子力显微镜（AFM）和 X 射线光电子能谱（XPS）等表面分析技术。还研究了分子量、温度和修饰对葡聚糖抑制效率的影响。所有应用技术的结果均表明，葡聚糖在 15% HSO 溶液中对 St37-2 钢的溶解具有中等的缓蚀性能。分子量为 100000-200000 g/mol 的葡聚糖（Dex 1）在 25°C 时表现出最高的 51.38%抑制效率。根据 PDP 结果，葡聚糖表现为混合型缓蚀剂。葡聚糖的抑制效率与分子量成反比，与温度成正比。采用两种修饰方法，即银纳米粒子（AgNPs）掺入葡聚糖基质和与 1mM KI 结合，来提高葡聚糖的抑制效率，这两种方法都很有效。在 25°C 下，通过注入 AgNPs，Dex 1 的保护能力从 51.38%提高到 86.82%，通过与 KI 结合，提高到 94.21%。温度影响的研究结果表明，在 60°C 下，15% HSO 环境中，Dex 1+KI 混合物对 St37-2 钢的保护作用可达 99.4%。表面分析结果证实了添加剂分子存在于研究金属表面。XPS 结果表明，AgNPs 以氧化物形式存在，而碘化物离子以三碘化物和五碘化物离子的形式存在于金属表面。修饰后的葡聚糖是一种很有前途的酸诱导腐蚀性环境用缓蚀剂候选物。
